Lubricating oil



Patented Feb. 4, 1947 UNITED LUBRICATING OIL Bert H. Lincoln, Ponca City, Okla, and Gordon D. Byrkit, Niagara Falls, N. Y.

No Drawing. Application May 16, 1945, Serial No. 594,161

16 Claims. (Cl. 252-32.?)

Our invention relates to lubricating oil and more particularly to improved lubricating oils of high film strength which are non-corrosive toward easily corroded bearing materials.

This application is a continuation-in-part of our co-pending application, Serial No. 405,213, filed August 2, 1941 (now Patent No. 2,395,889, issued March 5, 1946), which, in turn is a continuation-in-part of our application, Serial No. 275.488, filed May 24, 1939 (now Patent No. 2,257,750, issued October 7, 1941).

In the development of new automotive and other types of engines, increased power and other requirements have led to the introduction of bearing metals, alloys, and mixtures which are readily attacked by oxidation products of the lubricant. Some of these newer bearing compositions are cadmium-silver, copper-lead and alloys of lead with alkali, and alkaline earth metals. These comparatively soft metals are corroded readily by oil which have been used for a short time in the engine. One method of overcoming this difficulty would be to use more resistant bearing compositions, and another would be to use an oil which does not develop these corrosive materials during use. Still another method would be to use a lubricant containing a material which would react with and render inert the corrosive products as rapidly a they are formed. Our invention is not concerned with the first method but with the other two possibilities. Various addends have been proposed to be added to lubricantsfor the purpose of inhibiting the formation of corrosive materials during use. These may be called antioxidants, since they increase the time of use before rapid oxidation begins to occur and also decrease the rate of oxidation after it has started. Various addends have also been proposed to be added to lubricants for the purpose of reacting with such corrosive materials, as may in time be formed, and removing them from the oil so that they are unable to corrode the parts being lubricated. These may be called precipitants. The present invention proposes addends combining these two capabilities in the same molecule to give an unexpectedly superior activity'in both respects over whatwould be predicted from a simply additive effect.

Certain compoundsare adsorbed or absorbed by metal forming tenacious films at the surface I of metals which are able to stand high pressures. X-ray diffraction methods have shown that compounds containing highly polar molecules, that is, molecules of unsymmetrical character containing an atom or group of atoms exhibiting a sec- 'ondary or residual valence, tend to produce regimentation of the molecules of hydrocarbon oil when added thereto. A metal immersed in a strongly polar compound will show a film of the compound in which there is a. regimentation of molecules oriented with respect to the surface of the metal by which they are adsorbed or absorbed.

One object of our invention is to provide a substantially non-corrosive lubricant for use with the newer, easily corroded bearing compositions. It is to be noted, however, that the improved lubricant here described is advantageously employed with all types of bearings, since it is less corrosive during use with any of the metals: commonly encountered in practice.

Another'object oi the invention is to provide a lubricant inhibited against oxidation during use.

A further object of our invention is to provide a lubricant containing an addend capable of reacting with or otherwise rendering inert such corrosive products as may be formed during extended use.

Other objects of the invention will appear inthe following description.

Our invention consists of the addition to lubricants of all kinds of salts or soaps or certain sulfur-bearing acids. These saltsmay be of diverse types, and both the anionic and cationic parts of these soaps may be varied. Thus the cations may be purely organic or purely metallic or organo-metallic. In introducing sulfur into the acid radical of-our salts, we have found that certain compounds rich in sulfur react with unsaturated, relatively high molecular weight carbox'ylic acids to yield peculiarly effective addends for lubricating oils. By compound-s rich in sulfur, wemean those containing more than per cent of sulfur in their molecular composition, particularly polysulfides free from chlorine. Examples of these reagents are phosphorus pentasulfide, phosphorus trisulfide, and alkali metal polysulfides (sodium disulfide, potassium trisulfide, and higher sulfides). These particular sul-, furizing agents yield particularly effectively bound sulfur in the molecule of the sulizurized acid. The herein described salts of such sulfurized acids are extraordinary detergent and inhibitors of oxidation when added to lubricants of all kinds. They contain no corrosive halogen and are more efiective inhibitors than salts of acids containing sulfur in known structures such as sulfonic acids, sulfones, thioether-s, heterocyclic sulfur, and the like.

In the following examples, any of the cations may be used with any of the anions to form these soaps, and it is to be understood that each of these combinations when blended, suspended, or

otherwise mixed with a lubricant is an example of the invention. I

I. Anions A. Alkali metal polysulflde-treated acids acid 2. Sodium tetrasulflde-treated linoleic acid 3. Sodium trisulflde-treated linoleic acid 4. Sodium disulfide-treated elaidic acid 5. Potassium pentasulfide treated corn oilacids 1. Sodium pentasulflde-treated oleic 6. Potassium trisulfide-treated soy pentasulflde treated II. Cations A. Metallic Group IV Silicon Lead Tin Group V Arsenic Antimony Bismuth Group VI Tellurium Selenium Some or the organo-metallic radicals which may act as cations in forming the soaps to be used are:

Group II Phenylmagnesiu'm Iso-amylcadmium Propylmagnesium Butylmercury v Methylzinc Mesitylmercury Cresylzinc Nitrophenylmercury Xylylcadmium Naphthylmercury Group III Phenylboron (III) Diethylthallium Diphenylboron (I) Diphenylthallium o-Xylylboron (II) Di-p-tolylthallium Dipropylaluminum Group IV Triphenylsilicon Triethyltin Triphenylgermanium Triphenyltin Di-isoamyltin Di-isobutyllead Di-alpha-naphthyltin Diethyllead Diphenyltin Diphenyllead Ethylphenyltin Triphenyllead Iso-propyltin Group V Ethylarsenic Di-alphanaphthylbis- Diphenylantimony muth Diphenylbismuth Group VI Phenyltellurium Triphenyltellurium Diphenyltellurium Phenylselenium 1. Group 1: Lithium, sodium, potasslum, rubidium, cesium, copper; 2. Group 2: Calcium, strontium, barium, beryllium, magnesium, zinc, cadmium, mercury; 3. Group 3: Aluminum, gallium, indium, thallium;

4. Group 4: Titanium, zirconium, tin,

- lead;

5. Group 5: Arsenic, antimony, bismuth;

6. Group 6: Chromium, molybdenum,

. tungsten; 7. Group I: Manganese; 8. Group 8: Iron, cobalt, nickel. B. Organo-metallic Group II Magnesium Cadmium Zinc Mercury Group III Boron Thallium Aluminum 'The soaps derived from these organo-metallic radicals may contain in the organic radical or attached to the metal or in the anion of the soap, an additional element or combination of elements including the halogens, sulfur, phosphorus, nitrogen, or oxygen. 'Some of the combinations of the cations with anions arelisted below, but it is obvious that all the possible combinations serve as examples of the invention when admixed with lubricating oils or greases:

' 1. Sodium salts of sulfurized corn oil acids 2. Aluminum salts of sulfurized beta fat Stannous salts of sulfurized corn oil acids Stannic salts of sulfurized corn oil acids Ammonium salts of sulfurized soy oil acids Triphenyltin salts of sulfurized corn oil acids Diethylthallium salts of sulfurized corn oil acids d Phenylmagnesium salt of sulfurized oleic acid Nitrophenylmercuric salt of sulfurized lard oilacids Diphenylthallium salts of sulfurized soybean oil acids Triamylammonium salts of sulfurized' lard oil acids 12. Calcium salts of sulfurized corn oil acids 13. Lead salts of sulfurized beta fat 14. Barium salt of sulfurized oleic'acid, sul- Iurized with sodium pentasulfide 15. Triphenyltin salt of'suliurized oleic acid 16. Benzyltrimethylammonium salt of sulfurized oleic acid, sulfurized with phosphorus pentasulfide 1'7. Calcium salt of sulfurized oleic acid, sul- The addends of this invention have a multifunctional action in a lubricant. One action involves increased load-carrying ability and/or oiliness, while another action is directed to the furized with sodium pentasulfide 5 stability of the lubricant. For load-carrying 18. Calcium salt of sulfurized oleic acid, sulcapacity, quantities ranging from 0.1 per cent to furlzed with sodium trisulfide about 10.0-per cent must be added. As an anti- 19. Benzyltrimethylammonium salts of sulfurcorrosive agent-and/or antisludging agent, much ized corn oil acids, sulfurized with sodium smaller amounts must be used, ranging from appentasulflde l proximately 0.001 to 0.1 per cent. The action 20. Triphenyltin salts of sulfurized soybean oil of the compounds is specific but difllcult'to underacids, sulfurized with phosphorus pentastand. These compounds may be added to any sulfide. type of hydrocarbon lubricants but show an unb x 18 iv the usual value in highly refined and solvent-treated us1 iZl 1 -:s:its ie s c:i:edt :v: h2 5 fo ur id that parlubncants. ticular emphasis should be placed on theorgahm The lubricating oil portion of the blends of our metallic salts of sulfur-bearing acids because mvemfmn may be so'jcaned mineral or qm they are especially efiective antioxidants and corhon 0115 or m conslsii contain only rosion inhibitors; furthermore the tin salts m certain fatty 011s f com (metallic or organo-metallic) deserve notice as bean P l rd 011, and the like. lhe blends may exhibiting these properties to a high degree contam-voltohzed oils or synthetic 011s of lubri- The effectiveness of the oil addition agents of capmg vlscqslty soap'thlckened or Otherwise this invention is clearly demonstrated hereinggg used as greases g be f l below, in Table I, by comparative oil test results en 5 or otger pz Sue Pom for a mineral oil base and blends of the mineral depres sors may 8 presen oil base containing small amounts of related .T i compounds varymg degrees of addition agents; the outstanding one of which is blhty mhydrocmbon In some cases It contemplated herein. The firstfblend shown in necessary to E a Solvent for the compound or Table I contains a calcium salt of a sulfurized P fi colloldal suspens1n the compound oleic acid prepared by reacting oleic acid with m 1 elemental sulfur (S) followed by reaction with film sil'engih oxldatlon charactensmcs calcium hydroxide' and the second blend conof d em solid greases may be 1mproved tains a similarly prepared salt except that the by the addition of Small our metallic sulfurizing agent used was sulfur monochloride soaps thereto The 9 2 purity for as (S2C12). Neither of these blends is contemextreme P i i agents 15 mtFmmL plated herein. The third blend contains the All P is Important 1S F no corrosive corresponding calcium salt of a sulfurized oleic 212 22 i ig ifig m i 5 a number of acid wherein phosphorus pentasulfide (PzSs) was 9 mp0 S y emp Dye the sulfurizing agent Each salt contains 4 It will be understood thatcertaln features and stantially the same amount of metal and sulfur. subwmbmmns me of utmty and a be and had the same degree of acidity, as measured ploy-ed f q referepc? to other features and by their neutralization numbers. The mineral i Pm Thls 1S conpemplatefi by and oil base and blends thereof were subjected to an g z h z z gfi ofhour f g It f g oxidation detergency stability test at 300 F. for 6 anges em a total of 48 hours. At the end of the test, talls.wxthm the our claims Without the mineral oil base and blends were analyzed to ggi g the spmt of mveritlon i determine the increase in the color acidity as r one understood? at mventmn 18 measured by neutralization number (N N) and not be hmlted to the Speclfic details shown and naphtha insolub les, all of which indicate oxida- 5o fifiih, tion stability; and also analyzed for increase in A lubricant comprising in combination a lacquer dBDOSltSilIrd decrease n ash content, the major Proportion on of 1E1bricating viscosity analyses bemg mdlcatlve detergency and a minor proportion, suflicient to stabilize said stabl ty. The ts a tabulated m table oil against oxidation, of a salt of a sulfurized lowing: relatively high molecular weight carboxylic acid.

Table I tst 1. 11; ft 48 Per cent ash fiflrs st stt ggg gg g gg Conc' Weight I t 1d d m-Pmvmg age: m e True N \Y Naphtha 2%??? Origi- After color insolubles lacquer no] test deposits Weight percent 4 700 1 00 Per Mgsbo Calcium S-oleateleleinental s) "It? 300 I44 I54 26 "1336' ""613? Calcium S-oleate Estes) 1.0 335 .61 .40 23 .10 .07 Calcium S-cleate PS5) 1.0 300 .42 .02 .6 .10 .10

The foregoing results reveal that the salts of this invention are outstanding oxidation and sludge inhibitors, and are particularly effective detergents.

said carboxylic acid being unsaturated and being sulfurized by reaction with a phosphorus polysulfide containing more than fifty per cent of sulfur.

major proportion of oil of lubricating'viscosity' and a minor proportion, suflicient to stabilize said oil against oxidation, of a metallic salt of a sulfurized relatively high molecular weight .carboxylic acid, said carboxylic acid being unsaturated and being sulfurized by reaction with a phosphorus polysulfide containing more than fifty per cent of sulfur.

3. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, suflicient to stabilize said oil against oxidation, of an organo-metallic salt of a sulfurized relatively high molecular weight carboxylic acid, said carboxylic acid being unsaturated and being sulfurized by reaction with a phosphorus polysulfide containing more than fifty per cent of sulfur.

4. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, suflicient to stabilize said oil against oxidation, of a salt of an organic base and a sulfurized relatively high molecular weight carboxylic acid, said carboxylic acid being unsaturated and being sulfurized by reaction with a phosphorus polysulfide containing more than fifty per cent of sulfur.

5. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, sufficient to stabilize said oil against oxidation, of a salt of a sulfurized relatively high molecular weight aliphatic carboxylic acid, said aliphatic carboxylicacid being unsaturated and being sulfurized by reaction with a phosphorus polysulfide containing 'more than fifty per cent of sulfur.

6. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and. a minor proportion, sufficient to stabilize said oil against oxidation, of a metallic salt of a sulfurized relatively high molecular weight aliphatic carboxylic acid, said aliphatic carboxylic acid being unsaturated and being sulfur'ized by reaction with a phosphorus polysulflde containing more than fifty per cent of sulfur.

"7. A lubricant comprising in combination a major proportion of oil of .lubricating viscosity and a minor proportion, sufficient to stabilize said oilagainst oxidation, of an organo-metallic salt of a sulfurized relatively high 'molecular weight aliphatic carboxylic acid, said aliphatic carboxylic acid being unsaturated and being sulfurized by reaction with a phosphorus polysulfide containing more than fifty per cent of sulfur.

8. A lubricantcomprising in combination a major proportion of oil of lubricating viscosity and a minor' proportion, sufficient to stabilize said oil against oxidation, of a salt of an organic base and a sulfurized relatively high molecular weight aliphatic carboxylic acid, said aliphatic carboxylic acid being sulfurized by reaction with a phosphorus polysulfide containing more than fifty per cent of sulfur,

9. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, sufficient to stabilize said oil against oxidation, of a salt of sulfurized soybean oil acids, said soybean oil acids being sulfurized by reaction. with, a phosphorus polysulfide containing more than fifty per cent of sulfur.

10. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, sufficient to stabilize.

saidoil against oxidation, of a salt of sulfurized corn oil acids, said corn oil acids being sulfurized by reaction with a phosphorus polysulfide containing more than fifty per cent of sulfur.

11. A lubricant comprising in combination a ,major proportion of oil of lubricating viscosity major proportion of oil of lubricating viscosity I and a minor proportion, sufficient to stabilize said oil against oxidation, of a salt of sulfurized oleic acid, said oleic acid being sulfurized by reaction with a phosphorus polysulfide containing more than fifty per cent of sulfur.

, 12. A lubricant comprising in combination a and a minor proportion, sufiicient to stabilize said oil against oxidation, of a salt of a sulfurized relatively high molecular weight carboxylic acid, said carboxylic acid being unsaturated and being sulfurized by reaction with phosphorus pentasulfide.

13. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, sufficient to stabilizgsaid oil against oxidation, of the calcium salt of sul- '14. LA. 'lubricant comprising in combination a major proportion of oil of lubricating viscosity file of this patent:

and a minor'proportion, suflicient to stabilize said oil against oxidation, of benzyl-trimethyl ammonium salts of sulfurized corn oil acids, said corn oil acids being sulfurized by reaction with phosphorus pentasulfide.

15. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, suflicient to stabilize said oil against oxidation, of triphenyltin salts of sulfurized soybean ,oil acids, said soybean oil acids being sulfurized by reaction with phosphorus pentasulfide.

major proportion of oil of lubricating viscosity and from 0.001 to 10 per cent of a salt of a sulfurized relatively high molecular weight carboxylic acid, said carboxylic acid being unsaturated and being sulfurized by reaction with a phosphorus polysulfide containing more than fifty per cent of sulfur.

BERT H. LINCOLN.

GORDON D, BYRKIT.

REFERENCES CITED The following references are UNITED STATES PATENTS 16. A lubricant comprising in combination a of record in the 

